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66
Chapter 9 Registering Nortel 20XX and 11XX IP telephones
Operation issues
Table 9
provides solutions to potential problems.
Table 9 IP telephone troubleshooting
Problem
Telephone does not connect to
system
Slow connection between the
handset and the system
One-way or no speech paths
Change the contrast level
Block individual IP sets from
dialing outside the system.
Deregistering IP telephones
You can deregister selected IP telephones from the system, and force the telephone to go through
the registration process again.
Warning: After this feature is activated, all active calls are dropped.
To deregister a IP telephone from the IP record
1
You can access the deregister button from two locations:
•
Configuration > Resources > Telephony Resources > IP Terminal Details tab
•
Telephony > Sets > Active Sets > IP Terminal Details tab
2
From the top list, select the IP telephone that you want to deregister.
3
Click Deregister DN.
4
Reregister the telephone, as described in
Warning: After this feature is activated, all active calls are dropped.
N0060609 0.3
N0060609 0.3
Suggested solution or cause
If an IP telephone does not display the text
within two minutes after power up, the telephone did not establish
communications with the system. Double-check the IP configuration of the
telephone and the IP connectivity to the system (cables, hubs, and so on).
If the connection between the IP client and the system is slow (ISDN, dialup
modem), change the preferred CODEC for the telephone from G.711 to G.729.
See
Table
7.
Signaling between the IP telephones and the system uses the system port
7000. However, voice packets are exchanged using the default RTP ports
28000 through 28255 at the BCM, and ports 51000 through 51200 at the IP
telephones. If these ports are blocked by the firewall or NAT, you will
experience one-way or no-way speech paths.
When an IP telephone is connected for the first time, the contrast level is set to
the default setting of 1. Use FEATURE *7 and the
the contrast.
If you want to block one or more IP telephones from calling outside the system,
use Restriction filters, and assign them to the telephones you want to block.
Restriction filters are set up under Telephony > Call Security > Restriction
Filters.
"Determining the registration process" on page
Connecting to server
UP
or
DOWN
key to adjust
61.
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